Sac behavior after aneurysm treatment with the Gore Excluder low-permeability aortic endoprosthesis: 12-month comparison to the original Excluder device.

BACKGROUND: The original Gore Excluder endoprosthesis (OGE) used both during and briefly after clinical trials was associated with less sac regression and more sac growth than some other devices, even without apparent endoleaks, presumably because of transmural movement of serous fluid across the expanded polytetrafluoroethylene material. In July 2004, the device was modified to decrease graft permeability. This study evaluated the efficacy of the new Excluder Low-Permeability Device (ELPD) at 1 year and compared it with the OGE and the Cook Zenith device (ZEN).
METHODS: From Food and Drug Administration approval of the Excluder in November 2002 until June 2005, 283 patients underwent endovascular repair of abdominal aortic aneurysms with the Gore Excluder or the ZEN. Postoperative surveillance included computed tomographic scans at 1 and 12 months; 181 (64%) patients completed both scans. The 1-month computed tomographic scan served as a baseline, and the minor axis diameter, measured at the largest axial cut of the abdominal aortic aneurysm, was compared with the same measurement at 1 year. A sac size change of 5 mm or more was considered significant. Sixty patients treated with the OGE were compared with 72 patients treated with the ELPD. Forty-nine patients treated during the same time period with the ZEN, known for early sac shrinkage, were used as a reference. All measurements were performed by one observer from a digital workstation. Wilcoxon signed rank tests (pairwise) or Kruskal-Wallis tests (three groups) were used for intergroup comparison of continuous variables, whereas chi2 statistics or Fisher exact tests were used to compare categorical variables.
RESULTS: Patient age and sex and mean maximum aneurysm diameter at baseline were similar among groups (P = .59, .27, and .46, respectively). Graft migration, stent fractures, acute surgical conversion, late abdominal aortic aneurysm rupture, or aneurysm-related deaths were not observed. Type II endoleak rates were similar between ELPD and ZEN (23.6% and 20.4%; P = .68). Although a higher rate of endoleaks was seen with OGE (36.7%), this was not significant when compared with the other two devices (P = .11). At 1 year, patients treated with ELPD had a sac regression rate that was significantly higher than that for patients treated with OGE (63.9% vs 25%; P < 0.001) and was similar to that for patients treated with ZEN (65.3%). Significant sac expansion was not observed with ELPD.
CONCLUSIONS: At 1 year, similar to ZEN, significant aneurysm sac regression and minimal sac expansion were noted after endovascular repair of abdominal aortic aneurysms with ELPD. Low-porosity fabric used in the construction of endoprostheses seems to be an important factor in early aneurysm sac shrinkage. Long-term efficacy regarding the prevention of sac enlargement remains unclear, and further follow-up is suggested.